Background: The NHANES is a program of studies designed to assess the health and nutritional status of adults and children in the US. The survey is unique in that it combines interview and physical examinations. It is a continuous program that collects a nationally representative sample of 5000 persons in 15 counties across the country each year. Although symptom rating scales for depression and general well-being have been included in numerous surveys since the 1970s, diagnostic criteria for mental disorders in adults and children were not collected until 1998. Sections on Generalized Anxiety Disorder and Panic Disorder of the NIMH Diagnostic Interview Schedule for Children (DISC) version 2.3 were collected annually in representative samples of respondents aged 8 through 19 years in 1999 through 2004, and sections on eating disorders, elimination disorders, major depression/dysthymia, Attention Deficit Disorder/Hyperactivity, and Conduct Disorders from youth and/or parents were collected since 2000. There is a rich constellation of other correlates of mental disorders including demographics (e.g. age, sex, race/ethnicity, education, family income, country of birth), environmental exposures and risk factors (e.g. heavy metals, dietary pattern, physical activity), physical disorders (e.g. asthma, hypertension, diabetes, anemia, stroke, severe headache, thyroid condition), service patterns (e.g. seen or set up an appointment with a health professional for underlying mental disorder) and various biologic measures in the NHANES survey data such as DNA, lead, mercury, and thyroid hormone. Progress: Our analytic team has prepared merged data sets for demographic characteristics and mental disorders in children across the survey years from 1999-2004. We have completed the preliminary analyses of the prevalence estimates of GAD, panic, elimination, ADHD and conduct disorders, and prevalence estimates by youth, parent, and youth/parent combined for eating and major depressive/dysthymic disorders for the overall sample, by survey year, gender, race/ethnicity, and age. In order to assess the severity of these conditions, we have also calculated prevalence by four alternative impairment algorithms. These data will provide the first population prevalence data on these seven major mental disorders in children ages 8 through 19 in a national probability sample of the US. Future analyses will then examine the risk factors and biological correlates of these conditions in the general population. We will prioritize our analyses to address the key study questions that are the focus of our own research.